What a required minimum distribution is and why it exists
A required minimum distribution is the smallest amount the Internal Revenue Service will let you leave inside a tax-deferred retirement account once you reach the starting age. Every dollar in a traditional IRA, SEP, SIMPLE, 401(k), 403(b) or governmental 457(b) went in without being taxed and has compounded without being taxed. The RMD rules are the mechanism that eventually collects that deferred tax: they force a rising fraction of the balance out of the shelter each year and into your ordinary income.
The calculation is deliberately mechanical. You do not estimate your own life expectancy, and your health, your other income and your spending needs are irrelevant to it. You take one number from your account statement and divide it by one number from an IRS table. Everything difficult about RMDs is bookkeeping rather than arithmetic: which accounts count, which balance counts, whose life expectancy applies, and what happens when you get it wrong.
Roth IRAs have no lifetime RMD, and since 2024 designated Roth accounts inside a 401(k) or 403(b) have none either. That asymmetry is the whole reason people run a Roth conversion in their sixties: money moved into a Roth before the starting age never appears in this calculation again.
The formula, and where each number comes from
Divide the prior 31 December balance by the distribution period for your age. The balance is the fair market value of the account on the last day of the previous year, which your custodian reports to you and to the IRS on Form 5498. Do not adjust it for market moves since then, and do not net out this year's withdrawals: the divisor changes, the numerator does not.
The distribution period comes from the Uniform Lifetime Table, Table III in IRS Publication 590-B. It is a joint life expectancy for you and a hypothetical beneficiary exactly ten years younger, which is why one table serves almost everybody regardless of who they actually named. Two exceptions exist. If your spouse is your sole beneficiary for the entire year and is more than ten years younger than you, the real joint life expectancy is longer, so you use the Joint Life and Last Survivor Expectancy table, Table II, and get a larger divisor and a smaller distribution. If you are a beneficiary rather than an owner, you use the Single Life Table and an entirely different set of rules, which the inherited IRA RMD calculator handles.
The starting age moved twice in four years. The SECURE Act of 2019 raised it from 70½ to 72; the SECURE 2.0 Act of 2022 raised it to 73 for people born from 1951 through 1959, and to 75 for people born in 1960 or later. This calculator infers your birth year from the age and distribution year you enter and applies that schedule, which is why entering age 72 for the 2026 year returns nothing due.
Because the divisor is a life expectancy, the reciprocal is the fraction of the account you must take. At 73 that fraction is 1 ÷ 26.5, or 3.77%. At 85 it is 1 ÷ 16.0, or 6.25%. The required percentage rises every single year, which is the structural fact that makes RMDs a tax-planning problem rather than a cash-flow one.
Worked example: age 75 with a $500,000 IRA
You turn 75 during 2026, which means you were born in 1951, so your first distribution year was the year you turned 73. Your IRA was worth $500,000 on 31 December 2025. You have taken nothing yet this year, and your marginal rate on ordinary income is 22%.
- Find the divisor. The Uniform Lifetime Table gives a distribution period of D = 24.6 at age 75.
- Divide. $500,000 ÷ 24.6 = $20,325.20. That is the required minimum distribution for 2026.
- Express it as a percentage. 100 ÷ 24.6 = 4.07% of the account.
- Estimate the tax. $20,325.20 × 0.22 = $4,471.54 of additional federal income tax, assuming the distribution stays inside the 22% bracket.
- Price the failure case. If you took nothing at all, the excise tax under Internal Revenue Code section 4974 would be 25% of the shortfall: $20,325.20 × 0.25 = $5,081.30. Correcting it inside the statutory two-year window drops the rate to 10%, or $2,032.52.
Now change one thing. Suppose you had already withdrawn $25,000 earlier in the year. The required distribution is unchanged at $20,325.20, nothing is outstanding, and no excise tax is possible. The $4,674.80 of extra withdrawal is simply taxable income this year; it does not create a credit against next year's requirement.
Uniform Lifetime Table divisors and the percentage they imply
| Age | Divisor | Percent of balance | On $500,000 |
|---|---|---|---|
| 72 | 27.4 | 3.65% | $18,248 |
| 73 | 26.5 | 3.77% | $18,868 |
| 75 | 24.6 | 4.07% | $20,325 |
| 78 | 22.0 | 4.55% | $22,727 |
| 80 | 20.2 | 4.95% | $24,752 |
| 83 | 17.7 | 5.65% | $28,249 |
| 85 | 16.0 | 6.25% | $31,250 |
| 88 | 13.7 | 7.30% | $36,496 |
| 90 | 12.2 | 8.20% | $40,984 |
| 93 | 10.1 | 9.90% | $49,505 |
| 95 | 8.9 | 11.24% | $56,180 |
| 100 | 6.4 | 15.63% | $78,125 |
| 105 | 4.6 | 21.74% | $108,696 |
| 110 | 3.5 | 28.57% | $142,857 |
The dollar column is illustrative only: it applies each divisor to the same $500,000 balance, whereas a real account balance changes every year.
How to read the result
Treat the required distribution as a floor on withdrawals and a ceiling on nothing. You may always take more, and in many years you should: the required percentage at 73 is under 4%, well below what a large tax-deferred balance will eventually force out at 85 or 90. If your account grows faster than the required percentage rises, the dollar distribution grows too, and it can push you into a higher bracket, over an IRMAA threshold for Medicare Part B and Part D premiums, or into the range where more of your Social Security becomes taxable.
Compare the required percentage against the rate you would choose for yourself. A safe withdrawal rate of 4% and the age-75 required rate of 4.07% are almost identical, so at 75 the requirement is barely binding. At 85 the required 6.25% is well above most sustainable-spending estimates, and at 90 the required 8.20% is far above them. Past the mid-eighties the rules are draining the account faster than a planner would, which is exactly the intent: the tables are life-expectancy tables, not spending advice.
The excise tax figure is a worst case rather than a forecast. Section 4974 imposes 25% of the amount not taken, cut to 10% if you distribute the shortfall and file Form 5329 within the correction window, and the IRS will waive it entirely for reasonable error if you fix the shortfall and attach an explanation. Missing an RMD is embarrassing and expensive; it is rarely catastrophic if you act.
Mistakes that produce a wrong number
- Using the current balance instead of last year's closing balance. The numerator is frozen at 31 December of the prior year, whatever the market has done since.
- Aggregating plans that cannot be aggregated. You may total the RMDs of all your traditional IRAs and take the whole amount from any one of them. Each 401(k) and 403(b) must satisfy its own requirement separately, from that plan.
- Forgetting the sole-beneficiary spouse rule. If your spouse is more than ten years younger and is your only primary beneficiary, using the Uniform Lifetime Table overstates the requirement. The joint table gives a larger divisor.
- Assuming a Roth 401(k) still has an RMD. Designated Roth accounts inside employer plans lost their lifetime RMD requirement for years after 2023.
- Counting a Roth conversion as a distribution. You must satisfy the year's RMD first; the required amount is not eligible for conversion or rollover.
- Deferring the first RMD without doing the arithmetic. The 1 April grace period applies only to the first distribution year, and taking it means two taxable distributions land in the same calendar year.
- Ignoring qualified charitable distributions. From age 70½ you can send IRA money straight to a charity, and it counts toward the RMD while staying out of your adjusted gross income entirely.
Which edition this follows
The divisors here are the Uniform Lifetime Table as revised by the final life-expectancy regulations under Treasury Decision 9930 and published in IRS Publication 590-B, applying to distribution years from 2022 onward. The starting-age schedule follows the SECURE 2.0 Act of 2022, and the excise tax rates of 25% and 10% follow Internal Revenue Code section 4974(a) as amended by that Act. Confirm your own figures against the current Publication 590-B before filing, and treat this page as arithmetic rather than tax advice.
Where RMDs sit in a withdrawal plan
The required distribution answers a legal question, not a planning one. It tells you the minimum that must leave the account; it says nothing about whether that amount funds your life or whether taking it is tax-efficient. Three other calculations do the planning work around it.
First, size the spending. Work out how much you actually need each year and whether the portfolio supports it, using the portfolio longevity calculator or a fixed-rate rule. If your required distribution exceeds your spending, the surplus does not have to be consumed; it can be reinvested in a taxable account, where future growth is taxed at capital-gains rates rather than ordinary rates.
Second, manage the bracket. The years between retiring and the first RMD are the flattest income years most people ever have, and they are the window for partial Roth conversions. Filling the 12% or 22% bracket deliberately in those years shrinks the balance that later gets divided by a falling divisor. Model the trade with the traditional versus Roth comparison.
Third, if you need income before the starting age without the 10% early-distribution penalty, the substantially equal periodic payment route under section 72(t) is the alternative regime; the 72(t) SEPP calculator covers it. Note that the 72(t) rules use the same life-expectancy tables in a different way, and the two regimes never apply to the same person in the same year.
One more distinction is worth keeping straight. An RMD is a distribution requirement, not a sale requirement. You can satisfy it in kind by transferring securities out of the IRA to a taxable account at their fair market value, which keeps the position intact while still moving the taxable amount out of the shelter.